Exam 4 Flashcards by Cassidy Dixon

Triacylglycerols are stored in _______ cells in animals

Adipose

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The hormones _________ stimulate lipolysis when energy reserves are low.

Epinephrine and Glucagon

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The brain uses __________ instead of glucose for its source of ATP production during long-term fasting

Ketone bodies

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In diabetes, untreated chronic ketone body production will ______ blood pH levels.

Lower

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Beta oxidation of odd-numbered fatty acids produces acetyl CoA and ______

Propionyl CoA

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Fatty acids synthesis primarily takes place in the _______

cytoplasm

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________ is the product of the committed step in fatty acid synthesis

Malonyl CoA

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Citrate serves as signal for a high-energy state as it stimulates _______

Acetyl CoA Carboxylase

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Double bonds are introduced into fatty acids in the ________ compartment of the cell

Endoplasmic Reticulum

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Glycerol released during lipolysis is absorbed by the liver for use in:

Glycolysis and Gluconeogenesis

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Fats stored in adipose tissue is used by the liver and other tissues for:

Making ketone bodies and conversion of acetyl CoA for the CAC

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Fatty acids are linked to glycerol with:

Ester linkages

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Complete oxidation of palmitate yields _____ molecules of ATP

106

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Enzymes that digest the triacylglycerols into free fatty acids and monoacylglycerol are called:

Lipases

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Acetyl CoA carboxylase is globally regulated by:

Phosphorylation and desphosphorylation

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Intermediates from which pathways are utilized for fatty acid synthesis

Glycolysis
CAC
PPP

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Activation of acetyl CoA results in the production of

Malonyl CoA

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Which of the following is essential fatty acid?

Linoleate

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The carrier of an acyl chain through the synthetic protein complex is

ACP

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Excess NH4+ is converted into urea by the_____

urea cycle

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The hydrolysis of arginine by arginase produces ornithine and ______

Urea

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The urea cycle id linked to gluconeogenesis via formation of _____, a precursor of glucose synthesis

Furmate

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Succinyl CoA is a point of entry into the citric acid cycle of _______

Nonpolar Amino Acids

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_________ transfer amino groups from an amino acid to alpha-ketogluatarate

Aminotransferases

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An amino acid that serves as a nitrogen source in the synthesis of amino acids from alpha-ketoacids is ______

glutamate

The process of converting N2 to NH3 is called_____

Nitrogen Fixation

The final product pathway, which inhibits an enzyme that catalyzes its production typically, takes place at the ________ step.

Committed

Glutamine synthetase is an example of _______ inhibition

Cumulative Feedback

______ is a versatile nitrogen donor in the synthesis of a wide range of compounds

Glutamine

In the Urea cycle, the second nitrogen of urea enters the cycle in the form of which metabolite?

Aspartate

The urea cycle is

a way to remove excess NH4+

Which amino acids can be directly deaminated to produce NH4+

Serine and Threonine

In the urea cycle, free NH4+ is coupled with carboxyphosphate to form

Carbonic acid

Ketogenic amino acids are degraded to which metabolites?

Acetyl CoA and Acetoacetyl CoA

Organisms capable of carrying out reduction of atomspheric nitrogen include

Some bacteria

The carbon skeletons for amino acids are intermediates found in

Glycolysis, CAC, and PPP

Amino acids synthesized by humans are

nonessential amino acids

Transaminases use what as a coenzyme

Pyridoxine

3-Phosphoglycerate is the precursor for

Serine, Glycine, Cysteine

In bacteria, the _________ sequence is a purine rich region that is approximately 10 base pairs upstreams of the start site and directs the protein synthesis machinery to the start site

Shine-Dalgarno

________ si the initial amino acid in a bacterial protein

fMet

_______ include IF1, IF2, and IF3 in prokaryotes and are required for the invitation of protein synthesis

Initiation factors

G or translocase use the energy of _____ hydrolysis to move the mRNA by one codon in protein synthesis

GTP

In the ribosome, A stands for _______ and P stands for_______

Aminoacyl and Peptidyl

Proteins are synthesized from the ________ direction

amino-carboxyl

Sixty percent of human genes are regulated by____

mirco RNA

Eukaryotic mRNA is

circular

Chloramphenicol acts by:

inhibiting peptidyl transferase activity on the 50S ribosome

Peptide bond formation is

Exergonic and catalyzed by 23S RNA

What is the direction of translation of mRNA

5'-3'

Signals that define the beginning and end of protein synthesis are contained in:

mRNA

What factors are necessary for the correct placement of mRNA ash initiating tRNA on the ribosome?

IF1, IF2, IF3

Eukaryotic and prokaryotic translation differs primarily in which step?

initiation

What is the order of tRNA binding sites on the 70S ribosome with respect to the 5'-3' direction of the mRNA

EPA

Elongation factor G is also called what?

translocase

A group of genes under the control of a single promoter

Operon

________ is a required cofactor for RNA polymerase

Covalent Cation

DNA sequences that direct RNA polymerase to the initiation site are called________

Promoters

Expression of B-galactosidase requires the induction of an operon by removal of a______

repressor

Promoter sites in E.Coli are located _____ and ______ nucleotides upstream of the start site

-10 and -35

The first step of transcription in eukaryotes depends on the ______ subunit of RNA polymerase

Sigma

Cis-acting elements that have no promoter activity but can stimulate the effectiveness of promoters are called _______

enhancers

The enzyme that removes the acetyl group for a lysine of a histone is called_______

histone deacetylase

In eukaryotes, transcription is initiated by the binding of a transcription factor to the _____ box, which is located -24 and -32 upstream of the initiation site

TATA

The nuclear membrane is important in gene expression because it separates the processes of ______ from that of ______

Transcription and Translation

In prokaryotes function of RNA Polymerase are

- Searching for promoter sites - unwinding short stretches of DNA - detecting termination signals

The pribnow box is:

the site where promoters bind

The protein that binds DNA sequences and helps RNA polymerase initiate transcription is

sigma

In transcription, the 3' hydroxyl group

attacks the alpha-phosphoryl group on an incoming nucleotide

In E.coli what proteins are synthesized when B-galactosidase is synthesized?

- sigma 70 of RNA Polymerase - RNA helicase - Fibonuclease - galactoside permease

In eukaryotes RNA polymerase II

- is sensitive to alpha-amanitin | - catalyzes mRNA synthesis

In eukaryotes enhancer sites are often located

at a distance from the transcription start site

Differential gene expression is caused by

control of transcription

Cis-acting elements

are DNA sequences the regulate expression

Noncoding regions of RNA are called

intron RNA

RNA polymerase I is responsible for the transcription of

18S rRNA and 28S rRNA

What modifications are made to eukaryotic tRNA transcripts

- Modification of base and ribose moieties - An intron removed by endonuclease - Cleavage of the 5' leader by RNase P - The nucleotides CCA are added

The 5'cap of mRNA

- contains GTP in a 5'-5' linkage | - protects mRNA

The polypyrimidine tract

- is found at the 5' end of a junction - is found at the 3' end of an intron - contains a stretch of 10 pyrimidines

A spliceosome is made of

snRNP and snRNA

Thallasemia can occur when there are mutation in pre-RNA or splicing factors of:

hemoglobin beta

Ribozymes are

RNA

The carboy-terminal domain of RNA polymerase II

Binds factors need for pre-mRNA capping, splicing, and polyadenylation

A mutation in an enzyme that catalyzes a transesterification reaction would inhibit

mRNA splicing

Nearly all mRNA precursors in higher eukaryotes are modified by

Splicing

_________ catalyzes the synthesis of precursors for tRNA

RNA polymerase III

Recognition of the 5' splicing site by ____ is the first step in splicing

Self-splicing by RNA requires a ______ cofactor

guanosine

The immediate product go RNA polymerase II is referred to as _____

pre-RNA

The ______ is the elongated sequence added to the 3' end of mRNA

Poly A tail